A memory system including a NAND flash memory drives a plurality of chips in parallel to improve transfer performance.
As one kind of performance required of the NAND flash memory, there is data transfer performance during sequential write (hereinafter, “sequential write performance”). The sequential write is writing in which logical addresses designated by a host apparatus are basically consecutive. To improve the sequential write performance, it is important to increase the number of parallel writings as much as possible by, for example, simultaneously driving a plurality of chips.